Method of forming ingots



Sept. 16, 1924,

E. GATHMANN METHOD OF FORMING INGOTS Filed Feb. 12, 1924 2 Sheats$heet l Sept. 16 1924 3,50

E. GATHMANN METHOD OF FORMING INGOTS Filed F eb. 12, 1924 '2 Sheets-Sheet 2 I 6 new and usef within the sink head Patented Sept. 16, 1924.

UNITED STATES EMIL GATHMANN, OI BALTIMORE, MARYLAND.

mn'rnon or FORMING meo'rs.

- Application filed February 12, 1924. Serial no. e92,a 17.

' .To all whmaitmay concern:

Be it known that I, EMIL GATHMANN, a citizen of the United States, residing in Baltimore, Ma land, 'have invented certain Improvements in Methods of Forming Ingots, of'which the following isaspecification.

This invention relates to the casting of steel ingots in metallic molds to which the 1 molten metal is delivered through sink heads or feeders of refractory heat insulating material.

The ideal way to make sound ingots would be to pour the molten metal through the sink heads slowly and at intervals, i. e, to first pour a relativel small amount of the metal to fill the'mo d chamber to a small extent, then wait'a suitable time (the length of which depends on the cross section of Q the ingot) and then pour again, wait a short time, and then continue these operations until the mold' chamber is filled to the desired extent and until the ingot has solidified. In this way pipe or cavity due to 2 shrinkage would be practically eliminated.

As this" method would take from one to two and a half hours additional time in forming an ingot of say cross section and as the surface of the ingot would show a scabby formation where pourin recommenced, such to .be impractical. v

According. to my invention I pour the molten metalthrough a sink head into the mold chamberuntil the mold is nearly filled and the sink head partially filled, allow'the metalto partiall solidify or form a skin' on the surface o practice has been found After the mold chamber and the sink head are thus filled the. metal in the'mold' and sink head is allowed to cool and solidify and the ingot with the sink head'thereon may be removed from the mold in well known ways. In this process the pipe is formed wholly in that gart of the ingot an this end of the ingot may be are ped or rolled out or-forged and cropped in t e usual mg. I

My invention involves e. use; of sink was stopped andthe ingot, allow thefiuid steel in the sink head to lower or descend to heads or feeders of smaller size than-those commonly used, that is to say, the sink head is made of considerably smaller cross sec-, tion or diameter than theupper end of the mold chamber and when the moldjis first poured, the feeder is supported on the top of the mold by suitable devices which suspend the feeder in the mold. Afterthemold chamber and the sink head are filled" to the desired extent, andthesink head is partially filled, the supporting devices are withdrawn and the feeder is. supported onthe' partially solidified metal. After this the metal is allowed to aduallyocool and solidify from its outer si es and ttom inwardl and upwardly from them'oldwalls until thic walls areformed around the central molten metal mass. At this time additional hot molten metal the pouring is continued until the feeder is filled to the desired extent. When the metal has completely solidified in the mold chamber and in the feeder the pi or shrinkage cavity is eliminated from e mold chamber and the ipe'is contained wholly within the feeder". he ingot with the feeder may then be stripped from the mold in well known ways.

One-fourth 4 to shrinkage of=thediguid steel occurs in an ingot o twenty in es cross section in approximately eight to ten minutes and b my invention I am able to'use a sink head 0 amber of approximately one-halfthe volume ordinarily used in direct pouring of ingots -In the accompanyin drawings Ihave indicated the steps of t ev process ofcasting an ingot performed in accordance'with my invention. I

Figure 1 shows the first step where the mold chamber, which is definedbymetal chill walls, is filled through the refractory feeder or sink head to a short distancebelow its upper end, thefeeder 1 being supported on the top of the mold.

Figure 2 shows feeder supports are withdrawn and the feeder rests on the upper skin of the body of the ingot which through cooling has partiallvly solidified.

1 feeder after the ingot has solidified to a greater extent.

is pouredinto the feeder and r the next step where the Figure 4 indicates the position of the feedershown in the feeder has been filled with molten metal.

Fi e 5 shows how the ingot has complete y solidified and the pipe is located wholly within the feeder.

Figure 6'is a %lan view of the mold and i re 1.

Figure 7 is a p an view of the feeder shown in Figure 2.

1 Figure 8 is a perspective view of a feeder showing the lugs or ribs which as shown in Figure 1 rest on the feeder supports.

. The metallic mold indicated at M is preferably of the Gathmann type, the lower portion of the side walls being thicker than the upper portions thereof and being of the blg-end-up type. The feeder F is of refracgood heat insulating quali-.the series may e tory material of ty and may be either formed in one iece or th may be made of sections. It is provi ed with lugs or ribs f located referably mid-way between its upper and ower ends so that it is reversible, i. e. either end of the feeder may be inserted in the mold chamber.

By my invention ll am able to use refractory feeders of much smaller size than those commonly employed for an ingot of given cross section and weight. .llts cross section or diameter is much smaller than that of the upper end of the mold chamber with which it is used. Thus economy in the expense of the feeder which, as is well mown used for only one pour, or ingot, is obtained.

en starting the operation the feeder is i so supported on the top of the mold that it top of the mold extends a considerable distance into the mold chamber. For instance, in a mold having a chamber of twenty inches cross section, the feeder'should extend into the mold chamber a distance of from four or six inches and the cross section for a feeder of the size referred to should be about fourteen inches to sixteen inches thus leaving a clear space within the chamber around the lower end of the feeder of finm two to three inches, this space beingin the form of a ring bounded by the inner mold walls and the outer walls of that portion of the feeder within the I mold chamber.

' are preferably form tical axis is substantially'in line with the.

am's of the -mold chamber. This is indicated inFigu -e l where it will be seen the bars B re on the top of the mold and extend under the lugs or ribs f which integrally with the When the feeder is central vertical side walls of the feeder.

thus suspended, molten metal is poured mold, allowing t momma slight extent on the top of the metal as indicated at e.

lln making steel ingots a series of molds are usually fitted with sink heads. 1 For in stance if thirty-two ingots are made in one heat, each mold is fitted with a sink head and the metal is poured through the sink head until the metal rises to about the line indicated in Fi re l.- Then other molds in filled in the same way to e same extent until, say, eight or ten molds are thus filled, the feeders or sink heads of all these molds being supported by the bars 18 or similar devices. By that time the shin 'S in the. first mold poured is increased in thickness and the partially formed ingot has shrunken, leaving a deressed portion within the feeder or sink cad as'mdicated in Fi re 2 where it will be observed a portion 0 the skin while surrounding the lower part of the sink head does not extend across the metal within the sink head. The sup orting bars 18 may then be removed from the first he feeder or sink head to de scend with the shrinking ingot and to be supported thereby in the manner indicated in Figures 2 and 3. Then the sink head may be filled with molten metal in the manner indicated in Figure t, the molten metal breaking through any sli ht crust that may be formed on the top-of t e molten metal in the mold chamber. The this condition and the feeder or sink head of the second mold filled in like manner. The

first mold is then allowed to stand for a proper length of time until the metal has completely solidified when it will appear as shown in Figure 5, the pipe being entirely contained in the sink head as illustrated. In this way the pipe is formed within a relatively small crop end and thus much metal is saved and expense reduced and as before stated inasmuch as the sink head is relatively small, there is considerable saving in the cost of the sink head.

Shrinkage of a steel ingot commences with the formation of a skin in contact with the mold -walls. This solidification rapidly by dendritic crystallization uring the initial stages of the cooling of the ingot and after an. interval of a half minute the s in thickness materially increases and extends to the surface of the ingot, and into the ring a surrounding the feeder and a small pro esses how the metal quickly top of the molten llll) first mold may then be left in I is formed separating 1. and to .fill the sink isformed or confined.

ntoaeai thickness of skin is formed around the lower end of the feeder as shown in Figure 2 and, as shown in Figure 3, as the freezing continues' the thickness of the skin outside the.

also in contact with idification progresses the volume of the ingot becomes less in viewof shrinka e and the metal initially in the lower part 0 the feeder sinks-downwardly to compensate for the decreased volume due to shrinkage upon the formation of solidified steel. A cavity or recess is thus formed in the sink head chamher, the depth of which-increases in ratio to the time elapsed from the completion of the initial pouring.

As shown in Figure 3 of tlie drawing, shrinkage at this period has absorbed substantial y the greater part-of the li uid steel in the sink head casing. When s rinkage has progressed to this point which would take approximately from eight to ten minutes for an ingot of twenty inches in. cross section, repouring of the sink head is necessary to supply the additional hot liquid steelrequired to compensate for further shrinkage head where the final pipe The pouring just referred to should be rapidly accomplished .as otherwise an objectionable thick' skin or crust would occur, closing up the body of the ingot from the sink head casing. Sometimes a very thin skin the sink head chamber from the ingot body, but the addition of hot metal removes this thin skin and the filling of ltlhe body of the ingot is not interfered wit I As the cost of a sink head is proportional to its size and weight, it will be readily understood that a decrease in size of the sink head and whenuse'd according to my method,- greatly lowers the cost thereof.

Briefly stated my method consists of a preliminary pouring of ingot molds, using sink heads of relatively small size sus ended in the upper pzrt of the mpld cham re, a time interval ing allowedto elapse which *should be sufliciently long to allowthe mollike shape occurs wi adjacent to the sink head cham-f ten metal which has only partially entered the sink heads to shrink downwardly to com pensate for the initial body shrinkage of the ingot structure. During this period no true pipe is formed, but a de ressed area of saucer the molten steel entering and, her as indicated. in Figure 3. r I

' An ingot thus formed may remain in the Figures 2 and .3 for a period of from five to ten minutes while other molds are being similarly'jpouredp Before this the supporting bars should be removed Ingot solidification progresses removed.

within a period of from one-half to two minutesafter the shown in Figure 1 in order to allow the sink head to descend with the contracting ingot. After a period of five to ten minutes the first ingot poured is repoured so thatthe sink head is filled to a proximately its top as shown in Fi ure 4. v epouring should be in'the order 0 7 he pourings initially used in forming the ingots in the series of molds.

that a crust of material thickness should not be allowed to form over the entire surface of the molten metal. This crust or skin, however, should be allowed to form over the ansteel has risen to the level- By my method it is desirable but not essential nular outer ring of steel surrounding thesink head casing and under the walls of the' sink head so that the feeder may have a solid support and the suspending bars may be the removed at an early period. The steel from 'which the ingots are formed according'to my invention should be d'eoxidized as well as possible so that it is free from gases and wil set and solidify quickly.

By my apparatus and by my method substantial clearance between the mold chamber inner walls'and the outer sink head walls is obained. It should be observed that the strea of steel enteri the mold and sink head can be'stopped 0 when the sink head .is poured to the desired preliminary height which should be below the top of the mold as the ladle-man can see in the mold while pourin through the sink head b inspecting the rise of steel around the sin head. This he could not do if there were no. substantial clearance or space surroundin the sink head.

In. ro ling the ingot for reduction to" blooms and billets ordinarily a thin outer the height of pour wall about the sink head rolls out into very thin fins, which is very troublesome in passthus got. stantial or considerable amount these'fins are not produced. Another advantage of my invention is that a smaller and thus more economical feeder can be used 'with a larger clearance than with a smaller one or wherethe feeder fits closely. the moldv chamber. It is important to observe that inthe first pouring the metal the extreme top of the mold chamber orto overflow and the initial pouring is suspended as soon as the metal rises to the point indicated in Figure 1. Ina short time, say from one to two minutes in a cross section-mold, the supports If this were not done the metal reducing scabs on the body of the m y making the clearance space of subis not allowed to,rise to twenty inch B should be would freeze to the. sink head and would tend to draw it downwards. If left in this condition too long it would either break "the sink head or crack it or cracks would formed in the upper surface of the solidify and then mg ingot which would be extremely harml where a smooth finish'bloom or billet is desired. The advantage, therefore, of having the sink head first mounted on supports and then removing these supports and allowin the sink head to be supported on the solidi ying ingot itself will be apparent.

ll claim as my invention:

1. The method of forming an ingot, which consists in pouring molten metal through a sink head supported on the top. of a mold with its lower portion within the mold chamber until the mold chamber is filled with molten metal to the desired extent and surrounds the lower portion of the sink head and extends within it; allowing the metal to partially solidify and'the sink head to descend, then pouring molten metal into the sink head while supported on the partially solidified ingot until the sink head is filled to the desired extent andthen allowing the entire mass of-metal to completely solidity.

2. The method of formingan ingot, which consists in pouring molten metal into a mold chamber through a sink head of materially smaller cross section than that of the upper portion of the mold chamber, continuing this operation until the mold chamber is nearly filled and the molten metal rises around the sink'head and extends within it; allowing the molten metal to partially solidily and causing it to support the sink head allowing the entire mass of metal 7 within the mold chamber and within the cross section than that of the latter is filled to the sink head to completely solidify.

3. The method of forming an ingot, which consists in ouring molten metal into a mold chamber t rough a sink head of smaller cross section than that of the upper portion of the mold and the lower portion of which extends into the mold chamber, continuing the operation until the mold chamber is nearly but not completely filled with molten metal which surrounds the lower portion of the sink head and enters the lower portion thereof, waiting until a cavity has formed within the sink head ontop of the molten metal within the mold chamber, then filling the sink head to the desired extent and al lowing the entire mass of metal within the mold chamber and the sink head to completel solidify.

4. 'll he methodofforming an ingot in a metal mold, which consists in pouring molten metal into the mold chamber through a materially smaller the upper portion of the mold until the mold chamber is nearly but not completely filled, allowing the metal to partiallygsolidify within and around the sink head, allowing the sink head to sink with the partially solidified ingot, then pouring metal into the sink head until desired extent and suspended sink head of cences;

then allowing the entire mass of metal within the mold chamber and the sink head to completely solidify.

5. The method of forming a steel ingot in-a metallic mold, which consists in pouring molten metal into the mold chamber through a sink head of relatively small mold, until the mold chamber is nearly tilled and the metal surrounds the lower portion of the sink head, allowing the metal to partially solidify in such manner as to form a skin around the molten metal and beneath the bottom of the sink head, withdrawing the sink head supports and allowing the sink head to lower in the mold chamber while resting on the partially formed ingot, then pouring molten metal into the sink head until it is filled to the desired extent and then allowing the entiremass of metal within the mold chamber and within the sink head to completely solidify.

6. The method of forming an ingot in a metal mold, which consists in pouring molten metal into the mold chamber through a suspended sink head of smaller cross section than that of the upper portion of the mold chamber until the mold chamber is nearly filled and the molten metal enters the lower portion of the sink head and surrounds it, allowing the metal to partially solidity, then withdrawing the supports ofthe suspended sink head and supporting it on the solidifying ingot until thesolidification has somewhat progressed, then filling the sink head to the desired extent and then allowing the entire mass of metal in the mold chamber and in the sink head to completely solidify. 7. The method of forming ingots in a series of metal molds which consists in successively the mold chambers with molten metal t ough suspended sink heads of relativel mall cross section until each mold is fil ed to the desired extent, then allowing the metal in each mold to partiall solidify and the sink head to lower in t e mold chamber with the shrinking ingot, then after further solidification, tilling each sink head to the desired extent with molten metal .11m; with the first mold poured, then successively filling the sink heads of the. remaining molds in the series and then allowing the metal within the mold chambers and the sink heads to solidify com letely both within the mold chambers and within the sink '8. The method of mum; 9 which consists in pouring molten metal through a refractory sinkhead casin. supporte on the top of a metallic mol with its lower portion wit the mold chamber until the mold chamber is filled with molten metal to the desired, It for forming the cross section supported on the top of the y till lltl) bod of the ingot, and surrounds the lower solidified ingot until the sinkhead is filled portion of the sinkhead casing end extends to the desired extent and then allowing the within it, allowing the metal to solidify in entire mass of metal comprising the ingot an annular s ace surrolinding the sinkhead to solidify. I

5 casing and 1n contact therewith and the In testimony whereof, I have hereunto sinkhead to descend with the body of the subscribed my name. ingot, then pouring. molten metal into the sinkhead while supported on the partially EMIL GATHMANN.- 

